That's because there is no "Hide DLC I Don't Own" checkbox. It's "Hide DLC", it doesn't filter whether you own it or not. You hide all DLC, or no DLC. Would be nice to have the option added though. Add a filter similar to the DLC Inclusion one in My Settings, for which to show. On the My Achievements page, don't use a checkbox for Hide DLC, use a radio button for Show All DLC, Show DLC I Own, or Hide All DLC.

That's because there is no "Hide DLC I Don't Own" checkbox. It's "Hide DLC", it doesn't filter whether you own it or not. You hide all DLC, or no DLC. Would be nice to have the option added though. Add a filter similar to the DLC Inclusion one in My Settings, for which to show. On the My Achievements page, don't use a checkbox for Hide DLC, use a radio button for Show All DLC, Show DLC I Own, or Hide All DLC.

On my screen it shows 'Hide DLC I Don't Own'. Presumably this corresponds to your setting for whether all DLC is included or not.